My car has developed a strange noise when braking at lower speeds. The only way I can really describe it is it sounds like if you were to flex a piece of metal or stand on one of the thin metal drain covers. It will "pop" when coming to a stop and if there is enough momentum back it will "pop" back out. Otherwise, it will "pop" again when I set off. It started doing this after having the clutch replaced. I have had the rear front lower arms replaced as they were advised on my last MOT but this hasn't solved the problem. It sounds like it could be coming from the subframe somewhere. It's quite a loud noise.

It does sound like something is loose like a drive shaft bolt or caliper bolt. Bit odd for these to be removed when doing a clutch on a b6 though? 

Have you been back to the garage to check it out?